Numerical study on passive structural control of semi-submersible floating wind turbine considering non-collinear wind and waves

Floating offshore wind turbines have great potential in the deep-sea regions and they often suffer from the combined action of wind and waves, which affects the safety of wind turbines and the stability of power generation. At present, the tuned mass dampers installed in the wind turbine nacelles are widely used to control the vibration of wind turbine structures, but their mass are relatively small and have limited effectiveness on the large motion of floating offshore wind turbines. Moreover, the motion control of floating offshore wind turbines is mostly considered under the condition that the wind and waves are collinear while the non-collinear condition has been rarely investigated. Therefore, the tuned mass damper system installed in the nacelle and the platform of semi-submersible floating offshore wind turbine is studied through numerical methods in this research, and the non-collinear wind and waves conditions are considered. The results show that the high-frequency tuned mass damper installed in the nacelle is effective to reduce the response of tower but has little effect on the platform. The low-frequency tuned mass damper works well to control the response of tower and platform no matter it is installed in the nacelle or in the platform. For the irregular wave, the effect of tuned mass damper is not obvious and the large-mass one even increases the response. For the non-collinear wind and wave, the tuned mass dampers installed in the nacelle and platform at the same time have the best effect to reduce the response of wind turbine for various wind-wave angles. •The passive structural control of floating offshore wind turbine is studied.•The tuned mass dampers in both wind turbine nacelle and platform are investigated.•The action of non-collinear wind and wave on floating wind turbine is analyzed.